Filmmaker Rob Stewart dies off Alligator Reef

[Patoux01]

According to his sister, they wore dry suits. Check post # 40, in page 4 of this thread, posted by @Cali_diver:
Filmmaker Rob Stewart dies off Alligator Reef

Thanks for the link. Interesting that he didn't wear it 3 days before that dive however.

 

[Wookie]

Thanks for the link. Interesting that he didn't wear it 3 days before that dive however.

I expect you haven't dived the Queen? Some days it is positively balmy on the bottom. Other days it is in the 50's F. Last time I was in that area, I wore a 3 mil and didn't even get into deco. I wear a 3 mil for almost all of my Florida trimix diving, but never again on wrecks near the gulf stream. It's too easy to lose a dive because you weren't wearing enough exposure protection.

 

[Patoux01]

Indeed I haven't. Anything deep for me has only 3 solutions: thin wetsuit, drysuit, or redundant wings. I don't like the 3rd, and I'm fine in a drysuit for anything below 24°C.
But I doubt the suit Rob's wearing on the pic I gave is only 3mm, maybe it's not a picture that was taken a few days before then.

 

[Wookie]

Indeed I haven't. Anything deep for me has only 3 solutions: thin wetsuit, drysuit, or redundant wings. I don't like the 3rd, and I'm fine in a drysuit for anything below 24°C.
But I doubt the suit Rob's wearing on the pic I gave is only 3mm, maybe it's not a picture that was taken a few days before then.

As I said a few posts before, nothing beats training and experience. Maybe Rob's experience in a wetsuit in 200+ feet led him to reconsider his exposure protection. I know it has for me.

 

[CuzzA]

I'm trying to wrap my head around this a little... and thus, probably an ignorant question...

We hear about the "balanced rig" all the time, are there any consideration about this regarding a flooded unit? Some of these posts make it sound like a flooded unit is so negative that without redundant or overly compensated buoyancy one could be SOL and unable to swim up their rig.

I understand your training should prevent you from ever removing your mouthpiece without closing it, but are you guys considering an inadvertent kick to the face or a cut hose?

 

[St John the Diver]

It doesn't have to flood to get negative. The pressure of the water can completely deflate the counterlung so that it's simply empty albeit not full of water.

As for buoyancy, with AL19s my SF2 seems to be barely negative in fresh with min loop volume. I want to see how she is in salt, but I have a sinus infection to get over first.

Fill the can with water and see what happens.

You're talking a major difference when flooded.

 

[mderrick]

What happened may not have been a "flood" in the classic sense most would imagine. With a BMCL, removing the loop at the surface with an open DSV while the counter lungs are still submerged will cause the BMCL to rapidly collapse. This will cause the diver to immediately lose approximately 15 lbs of bouyancy, if they were neutral or near neutral then they will be completely submerged and sinking within seconds. To be clear, this is not a characteristic exclusive to the rEvo.

The diver has several options to regain control ( drop weight if so configured, inflate BC, inflate drysuit, maximum effort swim for surface, perhaps even inject gas into loop, and of course switch to OC bailout) but all these options assume very rapid and correct response by the diver. In my experience, especially for divers who switch between open and closed circuit configurations, the assumption of a rapid and correct response is questionable. As an instructor, I've seen students make all sorts of errors... Inability to rapidly recover their BC inflator, due to the inflator being in a different location than their OC rig, is commonplace. Failure to correctly operate their BC inflator, because for some reason panicked divers want to push the dump on the end rather than the power inflator button on the side, infrequent but I've seen it several times. Inability to rapidly recover OC off-board bailout is very commonplace because CCR divers don't routinely practice, perfect and maintain the skill or because of very subtle changes to equipment configurations such as have the BO clipped by the DM rather than the diver. In times of stress divers, for whom OC is their primary mode, will almost always return to OC habits and "muscle memory" regardless of their recent CCR training or experience.

I once had a new trimix CCR student who was unfamiliar to me. I always do a pool session and skills review before proceeding. Upon being given the hand signal to bailout, the student spit out the loop without closing it, fumbled around trying to find the OC second stage, gave up on that and started trying to unsuccessfully inflate their BC, even tried to put the loop back in their mouth... fully panicked, I'm convinced they would have drowned in 5 feet of water had I not jerked them to the surface (he said it didn't occur to him to just stand up)... trimix CCR student with 100 ccr dives and 20 hours of recent ccr experience, previously trained by a well known and well respected West coast CCR instructor.

DAN stats clearly document that loss of buoyancy control is a deadly circumstance.

 

[rjack321]

It would be profoundly stupid to not have these two on separate air sources...

edit: Or were they not using drysuits?

There are several divers near me who use a 19cf bottle on their CCRs for wing and drysuit gas. In various forums and in person many people have pointed out that this is a bad idea and violates all tenants of redundant buoyancy. They are still doing it.

Never underestimate the power of some people to rationalize their poor choices.

 

[St John the Diver]

What happened may not have been a "flood" in the classic sense most would imagine. With a BMCL, spitting the loop out at the surface with an open DSV while the counter lungs are still submerged will cause the BMCL to rapidly collapse. This will cause the diver to lose 15 to 20 lbs of bouyancy, if they were neutral or near neutral then they will be completely submerged and sinking within seconds. To be clear, this is not a characteristic exclusive to the rEvo.

The diver has several options to regain control ( drop weight if so configured, inflate BC, inflate drysuit, maximum effort swim for surface, perhaps even inject gas into loop, and of course switch to OC bailout) but all these options assume very rapid and correct response by the diver. In my experience, especially for divers who switch between open and closed circuit configurations, the assumption of a rapid and correct response is questionable. As an instructor, I've seen students make all sorts of errors... Inability to rapidly recover their BC inflator, due to the inflator being in a different location than their OC rig, is commonplace. Failure to correctly operate their BC inflator, because for some reason panicked divers want to push the dump on the end rather than the power inflator button on the side, infrequent but I've seen it several times. Inability to rapidly recover OC off-board bailout is very commonplace because CCR divers don't routinely practice, perfect and maintain the skill or because of very subtle changes to equipment configurations such as have the BO clipped by the DM rather than the diver. In times of stress, divers for whom OC is their primary mode, will almost always return to OC habits and "muscle memory" regardless of their recent CCR training or experience.

I once had a new trimix CCR student who was unfamiliar to me. I always do a pool session and skills review before proceeding. Upon being given the hand signal to bailout, the student spit out the loop without closing it, fumbled around trying to find the OC second stage, gave up on that and started trying to unsuccessfully inflate their BC, even tried to put the loop back in their mouth... fully panicked, I'm convinced they would have drowned in 5 feet of water had I not jerked them to the surface (he said it didn't occur to him to just stand up)... trimix CCR student with 100 ccr dives and 20 hours of recent ccr experience, previously trained by a well known and well respected West coast CCR instructor.

DAN stats clearly document that loss of buoyancy control is a deadly circumstance.

^^^ A++ on all of it.

Have seen it in the pool.
Have seen it in the headpool.
Have seen it at the back of the boat.

A relaxed and positively buoyant rebreather diver pops out the DSV to (laugh, smile, yell, swim) without closing it and is immediately swimming for his/her life.


On BMCL rigs buoyancy is lost almost immediately. And a flooded scrubber is almost certain.

On OTS lung rigs it's lots better. Not just a little better. LOTS better.

 

[St John the Diver]

There are several divers near me who use a 19cf bottle on their CCRs for wing and drysuit gas. In various forums and in person many people have pointed out that this is a bad idea and violates all tenants of redundant buoyancy. They are still doing it.

Never underestimate the power of some people to rationalize their poor choices.

Killed a guy on the Doria about five years back. A buddy on deco watched the dead diver float down past him as he hung on the line.